Without treatment, about a third of people with chronic hepatitis B infection go on to develop a disease of the liver, which can be very serious.

It is estimated that 15-25% of people with untreated chronic hepatitis B die of liver disease.

Cirrhosis

Scarring of the liver (cirrhosis) affects around one in five people with chronic hepatitis B, often many years after they first contracted the infection.

Cirrhosis doesn't usually cause any noticeable symptoms until extensive damage to the liver has occurred. It can then trigger symptoms such as:

• tiredness and weakness
• loss of appetite
• weight loss
• feeling sick
• very itchy skin
• tenderness or pain around the liver
• swelling of the abdomen
• swelling of the ankles

If you do develop cirrhosis, it is important to prevent it getting worse by avoiding drinking any alcohol, which has a damaging effect on the liver.

There are range of treatments that can sometimes relieve some of the symptoms of cirrhosis. Antiviral medication may help prevent further damage. However, for some people the only option is a liver transplant.

Read more about the treatment of cirrhosis.

Liver cancer

Around 1 in 10 people with cirrhosis caused by chronic hepatitis B will go on to develop liver cancer.

Symptoms of liver cancer include:

• unexplained weight loss
• being sick
• feeling sick
• jaundice 

Read more about the treatment of liver cancer.

Fulminant hepatitis B

An uncommon and serious complication of acute hepatitis B is known as fulminant hepatitis B, where the immune system attacks the liver and causes extensive damage to it.

Fulminant hepatitis B occurs in around 1 in 100 adults with chronic hepatitis B, but is much rarer in children.

It can lead to symptoms such as:

• mental confusion
• swelling of the abdomen caused by a build-up of fluid
• jaundice

This complication is a medical emergency and 7 out of 10 people will die from it.